Boring tool



May 3, 1927. 1,626,887

G. H. SPENGLER Filed July 5 1924 i Patented May 3, 1927.

' UNITED STATES PATENT OFFICE.

GEORGE H. SPENGLER, OF ROCKFORD, ILLINOIS, ASSIGNOR TO FRANK S. VANDER BOGART, F ROCKFORD, ILLINOIS.

BORING 'rooL.

Application filed July 5, 1924. Serial No. 724,279.

This invention relates to boring tools of the kind especially adapted to be used with a hand brace for cutting holes in plates or sheet metal of a diameter larger than made with the ordinary small sized drills, but adapted also to be used with power operated drills. V

Heretofore it has been the practice of mechanics, metal-workers plumbers and other artisans, when working without the aid of power drills, to cut such large diameter holes by drilling a series of small holes around a circle, cutting away the center and then finishing the, rough edge.

The primary object of the present inven tion is to provide an improved tool for b0ring large diameter holes of the character referred to; and to this end 1 have provided a rotary body having cutting blades secured to one end thereof by a center pin threadedly engaged in the body. By removing the center pin the cutting blades which are preferably in one piece, may be removed and another set of different cutting diameter may be substituted therefor.

l have also aimed to make the center pin in the form of a twist drill so that it will cut a pilot hole and by location therein will serve to guide the cutting blades. Thus the pilot hole and the final hole of larger diameter may be cut successively in what might be termed a single operation.

A further object is provide for very securely fastening the cutting blade to the rotary body as by seating the blade in a diametrical slot in one end'of the body and clamping the blade therein by means of a center pin or drill.

Another object is to provide an improved interchangeable cutting blade for boring tools of the character described.

Other objects and attendant advantages will be appreciated as the invention becomes better understood by reference to the following description when considered in connection with the accompanying drawings, in which Figure l is a side view of a boring tool embodying my invention; I

Fig. 2, is an end view of the boring tool looking at the cutter end thereof;

Fig. 3, is a similar end view of the boring tool with the cutting elements removed; and

Fig. 4, is a longitudinal section taken on the line 4-4 of Fig. 2.

Referring more particularly to the drawing, it will be observed that the tool body, designated generally by referencecharacter 5, preferably but not necessarily rectangular in cross-section, is shaped. at one end to pr0- vide a shank (5 adapted to be clamped in a brace, chuck or the like, and at its opposite end to provide a. slot or groove 7 extending diai'netrically of the major axis or axis of rotation of said body. This body of rotation may, however, be of any suit able shape but it is essential to my invention that it shall have a diametrical slot in one end for the, reception of a cutter body or element which has diametrically opposed cutting blades. v

In the preferred embodiment of my invention this cutter body is a stamping comprising a body portion 8 shaped to fit in the transverse slot 7 and having its ends turned at right angles to provide diametrically opv posed cutting blades 9 which extend parallel with the axis of the body 5.

The cutter body 8 is detachably secured to the body proper 5 by means of a center pin 11 which has a threaded end 12 passing through a center hole 13 in the cutter body and being threadedly engaged in a center hole 14 in the body 5, said center pin having a shoulder 15 clamped against the outer face of the cutter body. 111 the preferred form of my invention the clamping shoulder 15 is the inner face of a nut head 16 formed integral with the center pin. the latter in the rotary body. It will thus be apparent, that when the center pin is tightened in position the cutter body will be securely clamped in the transverse slot in the rotary body and confined by the side walls thereof agalnst rotary displacement and by the centerpin against displacement endwise of the slot. The slot 7 extends entirely across the end of the body .5 so that cutter bodies of different sizes, that is, for cutting holes of different diameters, may be used in the same manner as shown. In the present case the body 5 has a transverse The nut head facilitates tightening hole 17 which intersects the hole 14; merely to facilitate tapping the latter.

In the prefered embodiment of my invention the center pin is in the form of a twist drill as shown so that the center or pilot hole will be drilled by the same tool which cuts the larger hole, the drill serving .5 and 2:3 respeclively. 'lhese 'fm-es being mind after the (ids of il e curler Jlei l:

have been inrned up. 111 the n'esen'z': case the medial portion of lhe (fill/iii]? body is wider than he end portions r'nieh are in the slot 7 so 1125 not to Weaken the cro' l i the metal neetienzi :r'en d in removed by the center hole 13. In such case the L the slou i at rerep'tion oi ljhe "lied portion oi l eniilier bully.

it is believed l'hir (the mode or operzrlien o1 'ihrlee is obvious. .ln lhe event 'lhzil :1 plain eenier pin is used it will be heressziry lio drill a eenter pilot hole with an other drill for the reception of the center pin. The use. however, of :a twist drill for tl e center pin very desirable because it OXP'KIliTCS the drillin; and boring: operation nml'eoinbines into one iool lhe ope ntions which previously haul been performed with seweral 'l'ools. It Will be noted that the entler body is very firmly clamped to the rotary body so as not lie easily loosen or be (ll?- phired during; operation.

lb is believed,thziii lhe foregoing;- vonve vs :1 clear nnderslending of [The prinliples :ind objecis oi my inreniion and while I lrzve llnst iii-ed but. a single working einlilodinnnn' should be liii'ifilrl frlrfl'i that (hanger; niigrhl; mime ll. deiziiis of co trnetion Without rting from the spiri' and scope of ihe inrenl'ion as expressed in he appended Inn in which i claim:

A boring tool comprising a rotary body having a shank at one end, a threaded hole at its opposite end coaxial with the shank, a transverse slot in said ()plosite end exlending diametrically of s: id hole, {I (antler body reniorzibly fitting in said slot and hening at each side of said hole 2r cutter blade extending parallel with the axis of rot:- tion of the body pro 'ier, and :1 center pin threirdedly engaged in said hole and clamp-- ingg; the enile. body (:0 said bOdV proper.

GEORGE lil. Sllill lGLltR.

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